Using css and javascript, please help me write a program that takes in the average monthly rainfall for 3 months. I have written most of the CSS scripture its really the javascript I am having trouble with. Thank you

The program should ask the user to enter the following information: The names of THREE months. The amount of rain (in inches) that fell for each of these months. The program should display a message stating the average rainfall for the three months given. For example, if the user enters "June", "July", and "August" with average rainfalls of "3.3", "6.43" and "2", then your program should output something similar to the following: The average monthly rainfall for June, July and August was 3.91 inches. If the user enters invalid input (i.e., negative values, empty values), then output an error message to the console. Your program should not compute the calculation nor display the message with the months and average rainfall. As in, nothing but the error message should be outputted